1. Field of the Invention
The invention relates to a method and an apparatus for producing nitrogen in which air is compressed, cooled, cleaned, reheated and is finally passed through at least one membrane-type nitrogen separator stage.
2. Description of the Prior Art
Such a method of generating nitrogen is described in prior German Patent Application No. P 4404 072.5, which is not a prior publication. An air compressor is used therein which is cooled by the injection of oil, the oil being passed through a heat exchanger which for its part is used for reheating the cleaned air.
It has been found that this type of nitrogen production may be improved as regards its efficiency whilst at the same time reducing its constructional expense.
It is thus the object of the invention to provide a possibility for producing nitrogen more economically and with simpler apparatus.